European Delivery car insurance TWO DRIVERS

Have ordered BMW to pick up in Germany September 2013. My 26 year old son and husband are picking the car up at the Welt. Dealer we have placed order with told us that only ONE PERSON can be insured, and we cannot arrange for coverage for son to drive. Does anyone have advice/suggestions?

I took my European Delivery on June, 06 2013 and drove around Europe for a week by myself just because of insurance restrictions, of course my girlfriend drove my car too for few times without been listed as "covered driver" but that is the risk I took. German rules are very restricted and to get insurance for an extra driver's is way too much headache and definitely not worth the extra money.
Unfortunately the cost to cover another driver, going to a different insurance agency, is too high for someone with an international driver's license, it will be close to a rental car rates and we talking about some uncomfortable quantity of "euros" here.
BMW have no power to change the rules and they are not flexible when we try to change things like we do here in US, and I'm telling you, do the way they want and everything will be fantastic, follow all the instructions and whatever they suggest and you feel comfortable with, take it, you wont regret!
Another advise of an experience BMW guy, stay on the suggested BMW Hotels, the ones listed on the "European Delivery Package" that you probably already got in the mail, and tell your guys to enjoy it and record everything!!!